Question

A jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is $2 over 3$ Find the number of blue balls in the jar.

Solution

Total number of marbles in the jar = 24
i.e. n(S) = 24
Let number of blue balls in the jar be x.
Then, the number of green balls in the jar = 24 – x Let A be the favourable outcomes of getting blue balls. Then
n(A) = x
Therefore, P(A) = $fraction numerator straight n left parenthesis straight A right parenthesis over denominator straight n left parenthesis straight S right parenthesis end fraction equals x over 24$

Let B be favourable outcomes of getting green balls. Then
n(B) = 24 – x
Therefore, P(B) = $fraction numerator straight n left parenthesis straight B right parenthesis over denominator straight n left parenthesis straight S right parenthesis end fraction equals fraction numerator 24 minus x over denominator 24 end fraction$
According to the given condition :
P(B) = $2 over 3$
$rightwards double arrow space space space space space space space space fraction numerator 24 minus straight x over denominator 24 end fraction equals 2 over 3 rightwards double arrow space space space space space space space space 3 left parenthesis 24 minus straight x right parenthesis space equals space 2 space straight x space 24 rightwards double arrow space space space space space space space space 72 minus 3 straight x equals 48 rightwards double arrow space space space space space space space space minus 3 straight x space equals space 48 minus 72 rightwards double arrow space space space space space space space space plus 3 straight x space equals space minus 24 rightwards double arrow space space space space space space space space space space space space straight x space equals space 8 space$
Hence, the number of blue balls in the jar = 8.

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Real Numbers

A jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is $2 over 3$ Find the number of blue balls in the jar.

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Write the Sample Space when a coin is tossed.

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For Daily Free Study Material Join wiredfaculty

Real Numbers

A jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is Find the number of blue balls in the jar.

Some More Questions From Real Numbers Chapter

Write the Sample Space when a coin is tossed.

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

A jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is $2 over 3$ Find the number of blue balls in the jar.